Abstract. Double perovskites Sr 2 BOsO 6 (B = Y, In, and Sc) were prepared from the respective binary metal oxides, and their structural, magnetic, and electronic properties were investigated. At room temperature all these compounds crystallize in the monoclinic space group P2 1 /n. They contain magnetic osmium (Os 5+ , t 2g 3 ) ions and are antiferromagnetic insulators with Néel temperatures T N = 53 K, 26 K, and 92 K for B = Y, In, and Sc, respectively. Powder neutron diffraction

Orthorhombic V2O5 nanowires were successfully synthesized via a hydrothermal method. A cellconfiguration system was built utilizing V2O5 as the cathode and 1 M Mg(ClO4)2 electrolyte within acetonitrile, together with MgxMo6S8 (x ≈ 2) as the anode to investigate the structural evolution and oxidation state and local structural changes of V2O5. The V2O5 nanowires deliver an initial discharge/charge capacity of 103 mAh g-1 /110 mAh g-1 and the highest discharge capacity of 130 mAh g-1 in the 6 th cycle at C/20 rate in the cell-configuration system. In operando synchrotron diffraction and in operando X-ray absorption spectroscopy together with ex situ Raman and X-ray photoelectron spectroscopy reveal the reversibility of magnesium insertion/extraction and provide the information on the crystal structure evolution and changes of the oxidation states during cycling.

Nanostructured materials lie at the heart of fundamental advances in efficient energy storage and/or conversion, in which surface processes and transport kinetics play determining roles. This review describes recent developments in the synthesis and characterization of composites which consist of lithium metal phosphates (LiMPO(4), M = Fe, Co, Ni, Mn) coated on nanostructured carbon architectures (unordered and ordered carbon nanotubes, amorphous carbon, carbon foams). The major goal of this review is to highlight new progress in using different three dimensional nanostructured carbon architectures as support for the phosphate based cathode materials (e.g.: LiFePO(4), LiCoPO(4)) of high electronic conductivity to develop lithium batteries with high energy density, high rate capability and excellent cycling stability resulting from their huge surface area and short distance for mass and charge transport.

NH 4 + preintercalated V 2 O 5 •nH 2 O nanobelts with a large interlayer distance of 10.9 Å were prepared by the hydrothermal method. The material showed a large specific capacity of 391 mA•h•g −1 at the 500 mA•g −1 current density in aqueous rechargeable zinc batteries. In operando synchrotron X-ray diffraction demonstrated that the material experienced reversible solid−solution reaction and two-phase transition during charge− discharge cycling, accompanied by the reversible formation/ decomposition of a ZnSO 4 Zn 3 (OH) 6 •5H 2 O byproduct. In operando X-ray absorption spectroscopy confirmed the reversible reduction/ oxidation of V, together with small changes in the VO 6 local structure. The formation of byproduct was attributed to the dehydration of [Zn(H 2 O) 6 ] 2+ , which concurrently improved the desolvation of [Zn(H 2 O) 6 ] 2+ into Zn 2+ . Bond valence sum map analysis and electrochemical impedance spectroscopy demonstrated that the byproduct improved the charge transfer kinetics of the electrode. Cyclic voltammetry and galvanostatic intermittent titration technique showed that the electrode reaction was dominated by ionic intercalation where the discharge capacity in the voltage window of 1.4−0.85 V was attributed to the intercalation of [Zn(H 2 O) 6 ] 2+ , followed by the intercalation of Zn 2+ at 0.85−0.4 V.

Promising ZnMn2O4 anode provides high capacity in Li-ion batteries and the capacity increase during cycling due to the reversible Li storage in SEI and the extra redox reaction of Mn(ii)/Mn(iii).

Spectroscopic and X-ray diffraction operando techniques were used to investigate polycrystalline antiperovskite (Li 2 Fe)SO as cathode materials in a Li-battery setup. During Li removal, several intermediate, relatively stable phases exist. At low charging, Fe is oxidized from +2 to +3, but at higher charging, S 2− is also partly oxidized to elemental sulfur, suggesting a cathode bifunctionality, and both redox processes seem reversible. On cycling (Li 2 Fe)SO in a battery, spectroscopy data suggest that a part of the Fe atoms irreversibly vacate the high-symmetry positions in the crystal lattice, in line with the broadening of X-ray diffraction peaks. Instead, new, relatively broad reflections appear in the X-ray patterns that might be explained by a crystallographic superstructure, corresponding to a doubling of the cubic unit cell axis, but the peak broadness indicates a lowering in crystallographic symmetry. Using a standard electrolyte and a moderate charging rate of C/10 results in typical capacity loss per cycle, but by using an electrolyte with low sulfur solubility, the (Li 2 Fe)SO cathode is stabilized, and charge densities of more than 200 mAh g −1 at a 1C charging rate are obtained. Additionally, a Li-deficient precursor (Li 0.8 Fe)SO served as a cathode material in a Na battery, providing presumably reversible Na intercalation and removal.

The Li+ storage mechanism in a carbon composited zinc sulfide as an enhanced conversion-alloying anode material for Li+ ion batteries is studied by in situ methods. Further, it is found that the (de)lithiation processes are affected by a low charge transfer resistance, and the coated carbon can effectively improve the long-term cycling stability.

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